黑龙江多宝山古生代海盆闭合的岩石学证据

综合研究黑龙江多宝山地区古生代沉积地层、生物化石,通过分析侵入岩岩石地球化学及其锆石U--Pb 同位素测年资料,表明该地区早奥陶世至晚泥盆世早期为海相沉积地层,晚泥盆世晚期为海陆交互相沉积地层,早石炭世为陆相河湖沉积地层。多宝山海盆东南侧出露一套年龄为( 300 ± 3 ～ 357 ± 4) Ma 的花岗岩,其中正长、二长花岗质糜棱岩为后造山花岗岩,碱长花岗岩为造山后A 型花岗岩。表明多宝山海盆于晚泥盆世开始闭合,至早石炭世为陆相河湖沉积,晚石炭世-早二叠世为抬升剥蚀阶段。表现为多宝山地区于早石炭世开始造山,晚石炭世晚期或延至早二叠世发生造山后伸展作用。     

Biotic characteristics of the Sinian-Cambrian boundary beds in China and the boundary problems

There is general agreement that the first appearance of various small shelly fossils should be used to help delineate the beginning of the Cambrian Period. The history of research on this stratigraphic topic in China is briefly outlined and leads on to a discussion of the boundary problem in the light of information available both inside and outside China.The sections across the Precambrian—Cambrian (Sinian—Cambrian) boundary are described with notes on fossils in: (1) Tianzhushan section, Yichang, Hubei; (2) Maidiping section, Emli, Sichuan; (3) Wangjiawan section, Jinning County, Yunnan; and (4) Kunyang section, Yunnan.This is followed by a consideration of the biotic characteristics of Sinian—Cambrian Period. The history of research on this stratigraphic topic in China is briefly outlined and leads on to a discussion of the boundary problem in the light of information available both inside and outside China. This is followed by a consideration of the biotic characteristics of Sinian—Cambrian boundary beds, with respect to stratigraphy as well as organic evolution. The Precambrian—Cambrian boundary in China is estimated to have an age of 615 ± 20 Ma.It is commented that the above sections are qualified to be important candidates for the selection of the Sinian—Cambrian boundary stratotype and are also important working reference sections for the international Precambrian—Cambrian boundary stratotype.     

New data on Late Riphean volcanism in northern part of the Yenisey ridge

New species of organic fossils are described from the Precambrian Valday series on the Onega peninsula. This ancient Precambrian faunal locality was discovered in 1973; the first fossils described from it were pteridinians, assigned somewhat tentatively to the species Pteridinium simplex Gürich (AN SSSR, Izvestiya ser. geol., no. 12, 1974). The present article describes scyphomedusas assigned to a new genus and species (Albumares brunsae Fedonkin), typical Pteridinium simplex Gürich, Dickinsonia costata Sprigg, and new arthropod genera and species — Onega stepanovi Fedonkin and Vendomia menneri Keller. The species assemblage found shows that the Valday series on the Onega peninsula is of the same age as the Pound sandstones of Ediacara province in Australia. —Authors.     

从河南仰韶村到山西丁村——怀念袁复礼教授,并记“丁村旧石器”发现的一个序曲

本文简单记述了古脊椎动物与古人类研究所50年代几件有历史意义的活动,包括研究所的名称的由来,第一次野外考察,丁村旧遗址群的发现过程中的一些作者亲身经历的小插曲,供对科学史有兴趣的地学工作者的参考。此外,也提到一些关于我国几个著名的古生物(包括古人类)地点或遗址,当前在研究方面一些遇到的问题和对这些问题的个人看法。这些存在的问题,它们的产生是“自然的”,但可以减少重复,使工作更为有效和集中到了解科学问题本身上去。我们发表了不少数量的著作,但相对的信息则较少,深入解决问题的进度还可以更快一些。     

湘西震旦纪武陵山生物群的化石形态学特征和归属

湘西桃源理公港震旦系留茶坡组中部黑色页岩中的炭质压膜化石,为研究末前寒武纪晚期生物学提供了一个稀有的布吉斯页岩型分类学窗口。根据已知属种和新获材料的研究,确定了17个明显的形态类型,讨论了每种形态类型特征及其可能的生物学属性,指出除个别化石可能为两侧对称动物外,其余绝大多数化石可以解释为原核生物或多细胞藻类,系统发育上与绿藻、褐藻、蓝藻细菌等相关。具固着器、叶状体为球状或具同心纹构造的Apsidiumsphaericus的发现,进一步证明典型埃迪卡拉动物群(或白海生物群)中简单的圆盘状化石可能为多细胞藻类,而不是水母。武陵山生物群中具同心纹结构的大型圆盘状化石的出现及其共生生物特点,指示该生物群是埃迪卡拉期生物分异发展阶段的产物,是末前寒武纪晚期一个以多细胞藻类发育为特色的新型生物群。     

Discovery of Trace Fossils from the Sinian—Cambrian Boundary Beds in Eastern Yunnan and Their Significance for Global Correlation1

Abstract There are abundant and highly varied trace fossils in the Sinian—Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian—Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.     

A new 'Solenhofen' in Mexico

A new site has recently been discovered near Puebla, Mexico, at which fossils are found in a beautiful state of preservation in Cretaceous limestones. Most of the fossils are of new or little-known fish, but there is also a wide variety of invertebrates. The fossils have been found in a platy limestone that splits easily along the bedding planes containing the fossils. This type of preservation is very similar to that found at the world-famous fossil site at Solenhofen in Bavaria, Federal Republic of Germany, and may shed light on the community structure of this Cretaceous part of the geological column.     

Applications of molecular fossils in lacustrine stratigraphy

Biomarkers, or the so-called molecular fossils, are used tentatively in the Eogene lacustrine stratigraphy study in the Jiyang Sub-basin. Notwithstanding the fact that unidentified microfossils or amorphism and acritarchae are widely distributed in lacustrine source rocks, molecular fossils are useful to identify the sources. It is helpful to reconstruct the palaeo-enviroment, palaeo-ecosystem and compartmentalize the stratigraphic sequence by using molecular fossils with which the existence and types of microbes including bacteria, archaea and certain algae can be identified.     

Crinoid localities of the Devonian of the British Isles

Who collects the Devonian crinoids of south-west England? Since the nineteenth century, almost nobody. Few palaeontologists pursue these fossils, undoubtedly handsome in life, but indifferently preserved. Herein, we make a survey of four of the most important crinoid sites, all of which have the potential to produce new specimens.     

Excavating eurypterids,giant arthropods of the Palaeozoic

The eurypterids of the Silurian Bertie Group of North America are some of the most striking fossils known, with their dark organic cuticle outlined against a background of light coloured dolomite. Eurypterus is the most abundant genus but the pterygotids with their long grasping claws have fired our imagination as giant extinct predators. Large complete specimens are rarely found—the specimens are dominated by moulted exoskeletons that often disarticulate—but a giant that emerged from the rock more than 50 years ago is being prepared to go on display.     

Biogenicity of Earth's earliest fossils: A resolution of the controversy

The abundant and diverse assemblage of filamentous microbial fossils and associated organic matter permineralized in the ~ 3465 Ma Apex chert of northwestern Australia — widely regarded as among the oldest records of life — have been investigated intensively. First reported in 1987 and formally described in 1992 and 1993, the biogenicity of the Apex fossils was questioned in 2002 and in three subsequent reports. However, as is shown here by use of analytical techniques unavailable twenty years ago, the Apex filaments are now established to be bona fide fossil microbes composed of three-dimensionally cylindrical organic- (kerogenous-) walled cells. Backed by a large body of supporting evidence of similar age — other microfossils, stromatolites, and carbon isotopic data — it seems clear that microbial life was present and flourishing on the early Earth ~ 3500 Ma ago.     

西藏羌塘盆地光明湖地区早白垩世化石的发现及意义

西藏羌塘盆地以发育中生代海相地层为特征,成为近年来油气勘探的重要区块。对于整个盆地的中生代海相沉积是否跨入早白垩世过去仍存在一些争议。本次在光明湖一带的白龙冰河组上部采集到大量早白垩世化石,证实了该组沉积晚期已跨入早白垩世,为区域上与该组同时异相的其它中生代地层沉积时代的进一步厘定提供了新的化石依据。对整个羌塘盆地晚侏罗世—早白垩世沉积古地理的研究,以及羌塘盆地早白垩世海相地层的圈定和油气地质条件的探讨具有重要意义。     

鄂拉山北段早二叠世地层研究新进展

以现代地层学的理论为指导，将鄂拉山北段早二叠世地层新建切吉组，划分为三个段级地层单位，即：下段、中段和上段。将该套地层所含科化石作了进一步研究，划分出Ｎｅｏｓｃｈｗａｇｅｒｉｎａ带和Ｙａｂｅｉｎａ带     

A New Fauna——Qinghezhen Fauna——from the Northern Margin of the North China Platform

In the Inner Mongolia axis and Jiaoliao anteclise along the northern margin of the North China Platform.it has been found that the strata formerly considered as Archaean and Proterozoic are in fact an ophiolite suitesimilar to the Early Palaeozoic Ondor Sum Group in the Northern Geosyncline region of China. The stratahave been named in northern Liaoning as the Qinghezhen Group. The emphasis of this paper is on the discus-sion of the simall shelly fossils found in the siliceous rocks in the upper part of the Qinghezhen Group. Thisophiolite suite stretches in an E-W direction for about 1000 km along the northern margin of the North ChinaPlatform. in which 15 fossil localities with stable stratigraphic horizons have been discovered. In this paper. 4types. 7 genera (including 5 new ones) and 10 species (including 8 new ones and 1 new subspecies) aredescribed, which are collectively referred to as the Qinghezhen Fauna. The characteristics of these fossils are:shell form simple. the maximum length not exceeding 4 mm. with obvious shell wall and wall ornaments. TheQinghezhen Fauna is comparable in shell structure of some genera and species with the Meishucun Fauna inSouth China, but differs from the latter in having only monotonous fossil groups developed in a distinctly va-ried ecological environment. The two faunas may belong to the same evolutionary stage of the Early Cambrianbut have developed parallelly in different regions. The existence of the Qinghezhen Fauna represents an impor-tant biological event in the Early Cambrian in the Northern Geosyncline region of China. The discovery of theQinghezhen Fauna will bring new knowledge and profound influence to a series of problems on basic geologyand mineral deposit prospecting such as the Cambrian faunas. biogeographical povincialism in China and thegeotectonic features of the northern margin of the North China Platform.     

贵州遵义寒武系底部硅质岩中细菌状化石的发现

通过扫描电镜精细观测,在贵州遵义松林地区早寒武世黑色岩系剖面,于其底部的硅质页岩中发现了可能的细菌状化石,直径200～500 nm,形态不一,具有细菌的大小和形状,有机碳含量丰富,大部分细菌含磷.通过与已有报道中具相似形态生物体的对比,认为其可能是原生的、具有细菌生物结构的微生物小球体(Microbioids),本文称之为细菌状化石.这类细菌状化石可以赋存于石英颗粒表面、石英颗粒间,甚至嵌入石英颗粒中.据前人的模拟实验推测,细菌在石英颗粒沉淀过程中可能起到过重要促进作用,这从微观上为硅质岩的形成提供了新信息.     

Problematic fossils from the Palaeo-Neoproterozoic Vindhyan Supergroup, India

Fossils of the Vindhyan Supergroup exhibit extensive diversity and variable biologic affinities represented by: bacteria, cyanobacteria, algae, fungi, acritarchs, metaphytes and metazoans (including members of the Ediacaran Fauna) and ranging from less than a micron to almost a metre in size. Besides identified fossils, a number of bizarre morphologies (due to deviation of morphology from conventional structures), present in various stratigraphic horizons, have been observed. It is very difficult to identify and decide their biologic affinities. In thin sections of Lower Vindhyan cherts, microfossils resembling lichen-like or fungal forms in which a sac encompassing a coiled filament may possibly indicate a symbiotic relationship, a Volvox colony-like structure and a vase-shaped body without an opening are unique. Among the carbonaceous fossils, very unusual and interesting fossil is a transparent disc comprising numerous appendages of an unidentified mesoscopic insect-like organism. Megascopic branching and associated Grypania-like structure is another form preserved as impression on micritic limestone. Petrographic thin sections of chert belonging to the Sirbu Shale Formation, exhibit presence of microscopic bizarre forms. The assemblage includes acritarchs and acanthomorphs of variable morphology and a dividing cell-like structure interpreted to be of rhodophycean affinity or a cleaving embryo of an animal affinity. Other peculiar morphologies among the carbonaceous fossils are: branched filaments that have attached sporangia-like vesicles, Chuaria-like body comprising cluster of very small-sized spheroids resemble scale-like structure, a chrysophycean alga or a multicellular tissue of a metaphyte. Another carbonaceous fossil represents a possible metazoan exhibiting an elongate body and a mid-gut-like structure or a Vaucheriacean alga. Although the biologic affinities of these bizarre forms can be a matter of debate, their biogenic nature is almost undoubted. The presence of such forms in the Vindhyans indicates advancement in morphology and a gradual evolution of life during the Palaeoproterozoic–Neoproterozoic period. In addition, presence of Ediacaran fossils in Bhander Group and large-sized acritarchs especially Trachyhystrichosphaera sp. in petrographic thin section of chert from the Sirbu Shale Formation, Bhander Group, Upper Vindhyans, suggests Ediacaran age as an upper age limit of the Vindhyan Supergroup.     

Medusoid Fossils from the Sinian Xingmincun Formation of Southern Liaoning Province

Abundant medusoid soft-bodied metazoan fossils have been found in the Sinian Xingmincun Formation(with an isotopic age of 650 Ma) at Qipanmo, Qidingshan and Yangtun of the Dalian-Jinzhou area, southern Liaoning Province; in addition, a number of macroscopic algal fossils have been discovered for the first time in the Getun Formation overlying the Xingmincun Formation. Medusoid fossils include 3 genera and 6 species(all of which are new). Judging from their biological characters, these medusoid fossils are considered to have an intimate affinity with the Ediacara fauna in the terminal Precambrian of Australia, as their characters are close to each other. The authors suggest that these medusoids and the Edicara fauna might be the products of the same period. The discovery of the medusoid fauna in the Xingmincun Formation marks an important event in the evolution of the terminal Precambrian organisms in China, and it is of major practical significance in the study of the Sinian System of China and the correlation of the Sinian strata of northern and southern China.     

A new occurrence of Permian Seymouriamorphs in the U.S.S.R.

A large number of specimens of Seymouriamorph amphibian, family Discosauriscidae, were collected from the south slopes of the Kuramanskiy Khrebet, Mt. Sarytaypan, 10 km northeast of the settlement of Adrasman, Tadzhik S.S.R. Deposits yielding the fossils consist of about 70 m of effusive sedimentary rocks, the top third being tuffs, tuff sandstones, and tuff breccias, and the remainder being alternating fine-grained sandstones, argillites, and siltstones, of gray, greenish, pink, and black colors. The beds overlie 800 m of tuff lavas and tuff breccias and are overlain by 200 m of-tuff breccias. Fossil leaves are abundant in the lower half of the beds in all lithologic types, but the vertebrates are confined to about 1 m of adjoining layers of fine-grained gray to pink sandstone, and almost black argillite. The fossils consist of complete impressions of skeletons, which will yield much anatomical information. Two genera are represented, the most abundant referrable to the Central European form Discosauriscus. The other is related to the European Leptoverpeton but may be new. These specimens permit correlation of the Sarytaypan deposits with Lower Permian' bedsgqn Czechoslovakia and Germany. Larval forms are by far the most abundant, but the presence of adults affords a reliable comparison of growth stages. New and detailed information of the development of the spinal column will also be forthcoming from further study of the growth stages. Presence of gills in the larvae reaffirms the persistence of an aquatic larval stage in the morphologically reptile-like Seymouriamorpha. — N. Hotton III.     

西藏阿里札达盆地上新统鼠兔类牙齿化石的发现

首次在西藏阿里札达盆地上新世河湖相沉积地层中发现了鼠兔类牙齿化石，对鼠兔类牙齿化石的基本特征进行了描述，并在同一层位中采集了大量孢粉、古动物和古植物化石。结合区域地质特征，产出鼠兔类牙齿化石地层的古地磁、ESR测年资料，沉积学特征等的简要分析，认为札达盆地鼠兔类的演化迁徙与上新世时气候由温暖湿润向寒冷潮湿-温和干旱的变化有关。显然，这一发现有助于认识青藏高原新近纪上新世的生物演化、气候变化和构造活动，并为研究青藏高原新近纪以来的生物进化、湖泊与河流演化、气候变化、古地理与古环境变迁和古近系、新近系、第四系地层划分等提供了新资料。     

Textured organic surfaces associated with the Ediacara biota in South Australia

The Ediacaran Period takes its name from the fossils of the Ediacara biota, which represent the first appearance of large and diverse assemblages of organisms in the fossil record. Although the global record of these distinctive body fossils is now well known, a previously unrecognized megascopic organic record of textured organic surfaces (TOS) occurs in the Ediacara biota. However, TOS is also a feature over a wider range of paleoenvironmental settings, where body fossils are unknown, in Ediacaran siliciclastic successions that have been studied in Australia, Namibia and western North America.Paleoecological analysis of successive bedding planes of strata from the late Ediacaran Rawnsley Quartzite in the Flinders Ranges of South Australia, reveals that TOS represent the most common organic features in bedding-surface assemblages of the Ediacara biota. The TOS consist of preserved, patterned assemblages of textured organic mats, fibers and simple tubular body fossils. Complex Ediacara body fossils while striking for their distinctive body plans, and dominating some of the beds, are relatively minor components of combined overall surface area. Many elements of TOS have previously been miss-diagnosed as trace fossils, which are in practice limited to two or at most three morphotypes that indicate the presence of Bilateria. Although TOS represent a simpler grade of organismic construction than discrete and more complex Ediacara body fossils, they were preserved in a similar manner. Marked variability in all components of the biota between successive surfaces suggests that Ediacara ecologies fluctuated at short intervals despite an apparently consistent sedimentary regime.